I agree with T., your scope while not optimal for a rimfire will function just fine for probably 99% of what you are going to use it for.....plinking, critters,targets should not be a problem.
If you were interested in a Rimfire specific scope, Nikon has a New 2011 ProStaff Rimfire 3-9 BDC 150 with a Parallax down to 50 yards. I have this scope mounted on a Ruger 10/22 and have had nothing but fun with it. Using Nikon's Spot On Ballistic Program allows you to fine tune your accuracy even more with this scope.
Here's a pic of my rig right after I mounted it up.